[Speex-dev] size of speex packets when VAD/CNG is enabled

Ashhar Farhan farhan at phonestack.com
Tue Aug 19 01:59:20 PDT 2008


you can use the marker bit on the RTP.

- farhan

On Tue, Aug 19, 2008 at 12:04 PM, Fabio Pietrosanti (naif)
<lists at infosecurity.ch> wrote:
> Hi all,
>
> supposing to have speex working at 3.95, when VAD/CNG is employed, which
> is the size of those "silence" samples respect to voice samples?
>
> I am wondering if it could be possible to lower even the transmission of
> VAD/CNG samples by specifying "outbound" in the communication channel
> only 1 bit instead of sending the whole VAD/CNG packet.
>
> I am doing the same for AMR where i strip-off the AMR SID describing
> VAD/CNG and simply send "1 bit" in a custom appropriate header of the
> transmission protocol. With AMR 4.75, sample of 13byte, additionally i
> also cut-off the the 1byte AMR header by making AMR samples to be
> transmitted of 12byte.
>
> Are those kind of "bandwidth" optimization feasible also for speex?
>
> a) size of VAD/CNG samples being replaced by "1 bit" instead of
> transporting the whole sample
> b) cutting-off the speex header to reduce the sample size (and
> re-attaching it a standard-one on the other side before playing)
>
> I don't know if the first (a) or the second (b) would be feasible or
> would cause problems.
>
> Fabio
>
> p.s. i am talking about a voip application
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